In recent years, color light-sensitive materials have been diversified as seen in, for example, the color light-sensitive materials such as those for use in making color proofs. Light-sensitive materials to be used for these purposes are demanded to have characteristics comprising a high sharpness, being free of character blur, and high reproducibility of halftone dots and color balance for a color proof.
In the printing industry, the color proof is for a substitute process to curtail a trial printing step of the printing process of making prints from a color original. For the color proof, there are various known processes, including the silver halide photographic process, photopolymer transfer process, and toner transfer process.
In the photopolymer transfer process, the transfer process is not only so complicated that an image cannot be quickly obtained but also costly. In the toner transfer process, toner scattering occurs, so that it is not preferable from the environmental hygienic point of view. On the other hand, the silver halide photographic process is free of these shortcomings, less costly and well operable, so that a color proof can be rapidly finished up.
However, any of these commercially available color light-sensitive materials is inadequate in the reproducibility of halftone dots, so that a color proof having a correct color balance cannot be obtained. A high-sharpness color light-sensitive material having an antihalation layer containing colloidal silver is commercially available as well, but it has problems in that the whiteness of its background is deteriorated, its photographic gradation is softened, and so forth. Thus, there has been a demand for a color image forming method capable of giving a color proof having a high halftone reproducibility and color balance free of these problems.
As the method for improving the sharpness of a color light-sensitive material, there are known methods of:
(1) preventing irradiation by a water-soluble dye, PA0 (2) providing an antihalation layer containing colloidal silver or colloidal manganese, PA0 (3) raising the filling density of a white pigment in the polyolefin layer of a polyolefin-laminated reflection paper support, PA0 (4) thinning photographic component layers comprising a hydrophilic colloid, and PA0 (5) incorporating into photographic component layers a compound capable of releasing a development inhibitor at the time of developing.
The method (1) is utilized in those commercially available color light-sensitive materials for making color prints, but the water-soluble dye content of the material is so low that the reflection densities at wavelengths of 450 nm, 550 nm and 700 nm prior to developing the color light-sensitive material is lower than 0.5. Therefore, any color proof having an adequate sharpness and a correct color balance cannot be obtained.
The method (2) produces only an image inferior in the color balance as a color proof because the method deteriorates the white background of the image by a stain due to insufficient bleach-fix of colloidal silver as well as by a fog of silver halide of the light-sensitive material, and also heavily soften the photographic gradation. For this problem, Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 63034/1988 proposes a specific proportion of the gelatin and colloidal silver of the antihalation and adjacent auxiliary layers, and Japanese Patent O.P.I. Publication No. 63040/1988 proposes a specific thickness of the antihalation layer, but any of these proposals are still unable to provide satisfactory effects.
The method (3) is described in Japanese Patent O.P.I. publication Nos. 284763/1986, 270749/1986 and 270750/1986, but is unable to give any satisfactory image as a color proof.
The method (4) has its limits in thinning photographic component layers, thus being not so much effective as to improve sharpness.
And the method (5), although useful to emphasize the edge effect of an image having a low spatial frequency, is unable to produce any satisfactory image as a color proof.
In a color proof preparing method which uses a color light-sensitive material, various techniques for obtaining objective colors are disclosed.
For example, Japanese Patent O.P.I. Publication No. 141034/1978 describes preparation of a colored standard diagram and a method for determining an exposure time in accordance with the diagram. This method, however, although it enables the obtaining of objective yellow, magenta and cyan monochromatic densities, is unable to give any well color-balanced color proof comprising blue, green and red in the additive color process. Besides, the procedure for exposure in this method is complicated.
Japanese Patent O.P.I. publiCation No. 104335/1981 discloses a color proof making method which causes the overall photographic gradation of a light-sensitive material to be not less than 2.0. However, the publication makes no mention at all of the photographic gradations and the balance thereof at the toe of the characteristic curves of respective yellow, magenta and cyan color images. It describes examples of the color light-sensitive material including Fujicolor Paper 08, Fujichrome paper Type 31, Kodachrome 74RC. etc., but any of these are of a photographic toe gradation designed for making color paper prints from color films, and therefore not suitable for color proof making.
Japanese Patent O.P.I. Publication No. 1131139/1981 describes a method of making a color proof from a color light-sensitive material whose overall photographic gradation is not less than 2,0 and which, when exposed, contains other component colors. The method, however, is intended for correction of a discretional color, and is ineffectual in respect of the color balance.
Japanese Patent O.P.I. Publication No. 14651/1987 describes the use of a mask having dots in an exposure process. The method is to bring density changes to an image whose monochromatic densities are fixed, and has no relation with the color balance.